Hey Guys,

I am going to be running a GT 35/40 Single turbo setup, big streetport, and was wondering about Injector selection.

Would 4 1200CC injectors work?

Would this cause problems on bottom end?

Would this be enough fuel?

I was going to run the 2/550CC and 2/1680CC setup but am afraid that the Microtech setup will have troubles with this big of a jump in injector size.

Any thoughts?

David

 

Why don't you just add additional injectors?

 

Yes I could do this, but thats more cash, and more mods. If I can acheive a good state of tune with 4 injectors I think it would be the way to go.

David

 

This might help:
http://www.maxcooper.com/rx7/how-to/...tem/calcs.html

-Max

 

The microtech will do this jump, you will need to change the staging setup a fair bit tho,
better off to go some 720cc primarys if you can,

Dale

 

Max,

Your web site is pretty cool. You make me wish that I had passed high school math

David

 

nice website max.

 

i am having a problem in a friends car with the jump i size of injectors. i talked to a few people about how to cure this, and some people said they were just never able to get rid of it. in my own car, i did not have a problem, but in a friends car... holy ****! it was/is bugging the hell out of me because i could not figure it out after, and have not tried since. once the transition cleared it self up, the car runs like a rapped ape.

https://www.rx7club.com/forum/showth...hreadid=159158

in my setup i have chosen 2- 82LB inj and 2- 160LB injectors.

 

Okay,

I tried the calculations again on max's web site. According to these calcs, if I can keep the fuel pressure at at least 50psi and above I should be okay with 850's and 1200's, (which is how I asked that microtech set the base map.)

Here is my question, please forgive my ignorance if this sounds really stupid but:

is having fuel pressure of 50 to 65 PSI realistic?

Is this just a matter of buying a powerful enough fuel pump to meet the requirements?

David

 

I am glad you guys found the web page useful. I was doing lots of those calcs for a while, so I figured I'd make a web page to do it for me. I thought other people would find it useful, too.

Remember that changing the fuel pressure will change the amount of fuel delivered for a given injector pulse width or duty cycle. The ECU doesn't know about fuel pressure, so it doesn't compensate for changes. If you have the car tuned at one fuel pressure, it will run rich if you bump the pressure up, or lean if you drop the pressure. Be sure to re-tune (or scale some factor used to choose a pulse width in your ECU) to compensate.

-Max

 

Thanks for all the help Max

 

Very helpful webpage Max.